<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>表单应用</title>
</head>
<body>
    <h1>登录</h1>
    <hr>
    <form action="first_test.html" method="get">

        用户名：<input type="text" name="username"  required placeholder="底部提示必须是用户名">
        url：<input type="url" name="url" required placeholder="必须是url">
        手机号码：<input type="password" name="tel" required pattern="^1[358]\d{9}">

        <!-- 隐藏域 -->
        <p>
            <input type="hidden" name="user" value="100">
        </p>
        <input type="submit">
        <input type="reset">

    </form>
    
</body>
</html>